Details about Mr. Cook’s visit to the plant, in the city of Zhengzhou, located in the province of Henan, were not immediately available. Reuters reported that photographs provided to the news service by Apple dated Wednesday showed Mr. Cook smiling and meeting workers in the facility.

Apple, which contracts with Foxconn to produce iPhones and iPads, has had to confront a series of negative reports this year about labor practices at the technology manufacturing company. In January, The New York Times reported that workers assembling iPhones, iPads and other devices often labor in harsh conditions, according to employees inside those plants, worker advocates and documents published by companies themselves.

Mr. Cook’s visit to the Foxconn plant followed a trip to Beijing, where he met top leaders, reports said, including Mayor Guo Jinlong of Beijing and Vice Prime Minister Li Keqiang, who is regarded as the likely replacement for Wen Jiabao, the prime minister, who is expected to step down later this year.

The Chinese state-run news agency Xinhua reported that Mr. Li told Mr. Cook that China would strengthen intellectual property rights. He also said multinational companies should pay more attention to caring for workers and share development opportunities with the Chinese side, Xinhua reported.

In March, the radio program “This American Life” retracted a report based on a visit to a Foxconn factory by Mike Daisey, a monologist. The radio program found evidence that Mr. Daisey had invented several damaging details about his visit.